The P.I. submitting this FIRCA application holds a NIH R29 grant to study a malaria antigen, CSP-2, which is found on the surface of P. falciparum and P. berghei sporozoites. During the course of studying the species specificity of CSP-2, two novel P. vivax sporozoite non-CS proteins were detected. An anti-P. falciparum sporozoite sera detected a 15OkD crossreactive antigen in P. vivax, P. berghei and P. yoelli sporozoites. A set of Crossreactive monoclonal antibodies detected a 45/55kD antigen on the surface of P. vivax sporozoites. But work on these antigens has been severely limited due to the lack of availability of P. vivax sporozoites in the U.S. Researchers at the Centro de Investigacion de Paludismo in Tapachula, Mexico have extensive field and laboratory experience cultivating P. vivax sporozoites via the transmission of P. vivax infected patient blood to indigenous mosquitoes. The Proposal describes a collaborative effort to generate and characterize P. vivax non-CS protein specific monoclonal antibodies by adapting methods successfully used to identify and analyze CSP-2. These monoclonal antibodies will be employed to characterize the expression of their cognate antigens, including the two previously identified antigens, during the various stages of P. vivax development. Expression of these non-CS antigens will be compared in the two P. vivax CS protein variant strains present in Chiapas to determine if a monoclonal antibody to one of these antigens could be a more universal diagnostic reagent for P. vivax sporozoite infection than anti-CS protein repeat monoclonal antibodies. In addition, the biological activity of the monoclonal antibodies will be assessed during sporogony in mosquitoes and infection of human hepatoma cells in vitro. Inhibition of sporogony or invasion of hepatoma cells would suggest that the antigen may be a potential anti-sporozoite vaccine candidate.